I am facing an issue while using range search using KeyRange.

In lmdb, the following is stored:

key: event timestamp in millis
value: event payload

What I want to do:

• count query by for a given time range (how many events between 1000 hrs to 1010 hrs)
• fetch all the events for a given time range

Issue:

• if counts are queried using KeyRange.all(), correct count is returned.
• but, if queried using specific range, it does not return current count:
  • KeyRange.closed(min, max) returns 0

Observations:

• strangely, if queried using KeyRange.closed(min, max * numberOfKeys), it returns correct result.
• if the keys are dense, then things work as expected
  • say,

  long start = toMillis(LocalDateTime.of(2018, Month.JANUARY, 1, 0, 0));
  for(int i = 0; i < numberOfKeys; i++) {
    dbi.put(bb(start + i), bb(i));
  }
  

  • in this scenario, KeyRange.closed() etc. work as expected.

My question is :
am I using the correct APIs for my usecase? is it a configuration issue?

Note:

• Java version

  $ java -version
  java version "1.8.0_181"
  Java(TM) SE Runtime Environment (build 1.8.0_181-b13)
  Java HotSpot(TM) 64-Bit Server VM (build 25.181-b13, mixed mode)
  

• Windows 10 dev environment

A reproducible test case: gist